The large majority of home laundering agents available on the market today under the name of softeners are compositions based on quaternary ammonium salts containing two long-chain alkyl groups within the molecule, such as di-hydrogenated tallow-alkyl dimethylammonium chloride, for instance. This is because quaternary ammonium salts produce satisfactory softening effects on various fibers even when used in small quantities.
However, despite their remarkable softening effects on cotton and the like, the above-mentioned quaternary ammonium salts are less effective for synthetic fibers such as acrylic, polyester and polyamide fibers. Moreover, if they are used in high concentrations, the resiliency and the feel of clothes are adversely affected.
Furthermore, the above quaternary ammonium salts are so hydrophobic that when put in rinse water, they are not well dispersed at low to moderate pulsator speeds and tend to be deposited unevenly on the clothes. In addition, particularly when they are stored at low temperature for a prolonged time, these compositions tend to gain in viscosity and form gels or undergo phase separation. The commercial softeners contain, in addition to the quaternary ammonium salts, such additives as polyoxyethylene nonionic surfactants, electrolytes, solvents, and the like for improving the dispersibility and shelf life but the effects are not as satisfactory as desired.
Liquid softeners containing various amines as softener bases are also known. By way of illustration, a textile softening composition containing a long-chain alkylamine such as methyl di-hydrogenated tallow-alkylamines is described in JP-A-52-59796 (the term "JP-A" as used herein means "unexamined published Japanese Patent Application") (corresponding to GB-1514276); a textile finishing composition containing an acylated alkanolamine, a water-soluble quaternary ammonium salt and a fatty acid ester for imparting smoothness and the pleasing feel is disclosed in JP-A-58-60070 (corresponding to U.S. Pat. No. 4,446,034); a highly-dispersible softener containing a quaternary ammonium compound, a higher fatty acid-hydroxy(lower)alkylpolyamine condensate, and an alkylamine polyglycol ether is disclosed in JP-A-61-167083 (corresponding to U.S. Pat. No. 4,776,965); a stable aqueous dispersion for textile treatment which contains a di(higher alkyl)cyclic amine and a Bronsted acid is disclosed in JP-A-61-275474 (corresponding to U.S. Pat. No. 4,724,089); a softening composition containing a di-long chain alkylamine-anionic surfactant ion pair complex, a non-silicone wax and a liquid vehicle is disclosed in JP-A-64-85368 (corresponding to U.S. Pat. No. 4,913,828); a textile conditioning composition containing an amine such as a hydroxy(lower)alkylalkylenediamine-higher fatty acid condensate and an amphoteric textile conditioner is disclosed in JP-A-2-6662 (corresponding to EP-332270); a textile conditioning composition containing a di(long chain) alkylamine-polycarboxylic acid complex for imparting flexibility and antistaticity to fabrics is disclosed in JP-A-2-14076 (corresponding to U.S. Pat. No. 4,869,836).
Furthermore, JP-A-52-5394 (corresponding to U.S. Pat. No. 4,045,361) discloses a fabric conditioner comprising a mono- or di(long chain)alkyl-alkylenediamine antistatic agent and a quaternary ammonium softening agent.
However, these amine-containing softeners are not sufficient in the ability to soften the substrate fabrics, although they are superior to those softening compositions based on quaternary ammonium salts in dispersibility and shelf life.